Electrical braking



April 29, 1924.

H. R. MEYER ELECTRICAL BRAKING Filed July 22 Gr; an :1

Ground.

INVENTOR 5? Me 9/." Hag/7 WITNESSES: 22%.

ATTORNEY Patented Apr. 29, 1924 UNITEDFsrArEs HARRY n. MEYER, or wrnxmsnuno, r'nnnsrrvnnrnjnssrenon"r0'wns'riNGHoUsE ELECTRIC a MANUFACTURING comran'mn o'onronA'rIoNorPENNS LVANIA.

ELECTitICAL BRAKING.

r Application mes Jul 22 1921'. serial nuaasaos.

To all whom it'may'concemf: I Be it knownthat I, HARRY R. MEYER, a citizen of theUnited. States, and a resident of Wilkinsburg, in the count of Allegheny and State ,of Pennsylvania, liave invented a new and useful Im rovement in'Electrical Braking, ofwhich are following is a'specificationw, f a M invention relates to control systems and it has articular relation to controls sterns for e ecting electrical braking of a p urality of motors utilized wa vehicle.

. ne objectofmy-invention is to provide a method of effecting electrical braking of a plurality of vehicle motors upon failure of the air or the mechanical brakes. f 1 A second ob'ect of my invention is to provide ametho of effecting electrical braking of a plurality of driving motors upon the'failurejof the source of owerfthat energizes the actuating coils o a plurality of contactors of the control system." c

Another object of my invention is to make it relatively diflicult or. inconvenient for the operator to start the motors after. efiecting dynamic braking,. thereb tending to revent the operator from requentlyemp oying dynamic brakin when it is unnecessary. In this connection, it will be understood by those skilled in the art that dynamic braking tends to decrease the period of usefulness'of motors. j

I A further object of my'invention is to prevent the line switch from closing anda dynamic-braking circuit from being'established simultaneously. I

, Briefly speaking, my invention'eonsists in providing a switching device that may be actuated by an operator placing his foot thereon, if the master controller has been returned to its off. position, andby providing a latching'device which maybe operated only from without the car, thereby requiring the operator to leave his cab to release the latch ing device before he can re-energizethe con- '-tro1system. I It. is possible to have the latching device for driving a railso arranged that itmay be reset fro'm? some point remote fromthe motormans'etation, as the chief requisite isto so desi the' 'de- .vice thatthe motorman will be -clisincli'ned to employdynamic'braking frequently.

i For a .betterunderstanding of my invention, reference may be'made. to the accompanying drawing,

. Figure 1" Ofg'WlllOh is aschematic view of.

the -main circuits "of a control system embodyingmy invention;

.Fig. 2 isa. sequence chart showing the order of closure of a plurality of contactois- ,employed in the control system illustrated in Fig.1;

g Fig. 3 is a diagrammatic view of apert1on of the auxiliary control system em ployed tov govern-the contactors shown in Fig, .1 andof a switching device constructed lnfaecordance with my invention; and

"Fig.4 is a viewyinend elevation, of a portionwof, an electric railway vehicle on which acontrol system constructed in ac..

cordance with my invention is mounted.

'Referri-ng particularly to Fig. 1 of the drawing,-a.plurality of motors 1 and 2 hav-' ing. armatures 3and 4,,respectively, and corresponding field-magnetwindings 5 and 6,:

may be energized from a source of electrical energy, such for example, as a' trolley 7, through a trolley-pole 8 and a line switch 9. A starting resistor 11 is employed for governing the current traversing the motors 1 and-2. a Y

, A plurality of accelerating contactors 12, 13 and 14 are employed for shunting the starting resistor '11. Series cont-actor 15 and parallel-connecting conta ctors 16 and 17 are employed for connecting the motors 1 and 2 in series and in parallel relation, in accordance with well-known practice.

A master jreverser 18 is employed for reversing the connections of the series field- -'--movable contact segment 26 and a plurality of contact terminals 27 to 30, inclusive, is I provided with an: .-ofl,?z- "position and a plurality of operating posit-ions. An auxiliary or control resistor 31 is employed for energizing the actuating coils of the contactors that are illustrated in Fig. 1 of the drawing, in accordance with a familiar practice.

The switching device 19, which has been partially described previously in connection with the main circuits that are illustrated in Fig. 1. romprises a casing member 32, a cover member 33, which is preferably placed at the same elevation as the car floor and constitutes a part thereof, and the insulating base member 21 on which the movable switch member 22 is pivotally mounted by means or" a holding member or switch jaw 3 1. The movable member, 22 is biased to its upper position, which is that shown in Fig. 3 of the drawing, by means of a resilient member 35, which is mounted upon a suitable guide member or rod 36.

The movable member 22 may be actuated to its closed position by pressure upon a push-button device, such as a bolt 37. A latching device 38 is pivotally mounted upon the base member 21 by means of a pin 39. A spring -11 tends to rotate the latching device 38 in a clockwise or latching direction. a stop member 42 limiting the travel of the latchingmember. The latching member 38 is provided with an enlarged end portion 4-3 which prevents the movable member 22 from returning to the position illustrated by solid lines in Fig. 3 of the drawing after the member 22 has been once actuated to the position illustrated by broken lines in Fig. 3.

The latching device 38 may be released by applying pressure to the handle 44 in a counter-cloclnvise direction. The handle 44 projects under the car body 45, as illustrated in Fig. 4-01 the drawing, and thus it is necessary for the operator to dismount from the car to enable him to actuate the latching; member 38.

A pin, or holding member 46 is slidably mounted upon a stationary block 47 to prevent the movable switching member 22 from being actuated to its closed position when the actuating coil of the line switch 9 is energized. in a manner hereinafter more fully described.

An armature or core member 48 is mechanicall connected to the pin 46, being biased to the position illustrated in Fig. 3 of the drawing by means of a spring 49. An actuating coil 50, which is connected in series relation with the actuating coil of the line switch 9, is employed to actuate the armature member 50 toward the stationary contact member '23, thereby causingthe pin 16 to assume its locking position, which is illustrated by broken lines in Fig. 3.

An interlock 51, comprising a plurality of stationary contactfingers 52, which are secured to the casing member 32, and a movable member 53, which is insulatedly mounted upon the movable contact member 22, prevents the energization of the actuating coil of the line switch 9, unless the switching device 19 is in its normal or oil position which is that shown in the draw- The operation of the control system in Fig. 1 will be understood by those skilled in the art, and, therefore, will be described only in a general manner. The motors 1 and 2 are first connected in series relation by the closure of the line switch 9 and the series contactor 15, in accordance with step a of the sequence chart, shown in Fig. 2 of the drawings. Starting resistor 11 is then shunted by closure of the accelerating contactors 12, 13 and 14, in accordance with steps b. 0 and d of the sequence chart.

The motors 1 and 2 are next connected in parallel relation by means of the line '1 and 2.

After the master controller has been actuated to its reverse position, the operator steps upon the bolt '37, thereby actuating:

the movable contact member 22 downwardly past the head 43 of the latching device 38 until it engages the stationary contact member 23. The pin 46 is actuated to the posi tion illustrated in Fig. 3 by the spring 4 under nolmal conditions. that is. during the de-energization of the actuating coil 50.

The latching member ilflis at this time so actuatedby the spring 4.1 that the head 43 of the latching member 38 prevents the movable contact member 22 from being actuated upwardly by the resilient member 35.

Then the movable contact member 22 has been actuated to its lower position, and motor field-windings 3 and 4 have been reversed; a dynamic-braking circuit is established (see Fig. 1 of the drawing) from Ground through the main reverser 18, series field-magnet winding 6 and armature 4 of the motor 2. starting resistor 11, armature 3 and series field-magnet winding 5 of the motor 1, main reverser 18, and stationary contact 'meniber 22 and movable contact member '23 of the switching device 19 to Ground.

"It is apparent by an examination of Fig. l that no electrical energy is required to actuate any of the contactors illustrated in could, if desired, be operatedmanually.

'lVhen the operator has brought the car to astop, it" is necessary forhim to dismount and actuate the latchingmember 38 in a counter-clockwise direction, by means of the I handle 44, before he can reenergize the motors 1 and 2; for the reasonthat the actuating coil of the line switch 9 can not be ener-.

' gized. when the movable-member). is actuated was lower position, as the" contact segment 53 no longer engages the control fingers 52. As soon-as the head 43 ofthe latching member 38.n longer engagesthe movable member 22, the resilient member actuatesthe movable member 22 in a clockwise direction, thereby breakingthe dy-' namic-braking' circuit. 7

When the movable member 22 has returned to its upper position, as shown in Fig. 3 of the drawing, the interlock formed by the contact segment'53 and the control fingers 52 is closed.

When the master controller 25 is actuated to its off position, or to either its series or its parallel position, a circuit is established from the trolley'7 through control fiingers 27 and 28, which are bridged by the contact segment 26 of the master controller 25, a portion of the control resistor 31, actuating coil of the line switch or circuit-breaker 9, the actuating coil 50, constituting a part of the locking device 46 of the switching device 19, and control fingers 52, which are bridged by contact segment 53, to Ground.

When the actuating coil is energized, the solenoid 48 is drawn toward the stationary holding member 47, and the lock member 46 projects below the movable member 22, as indicated by broken lines in Fig. 3. So long as the actuating coil 50 is energized, the locking member 46 prevents the movable member 22 from being actuated downwardly. a

To de-energize the actuating coil 50, it is necessary to return the master controller 25 to its off position. Because of this action, a short circuit can not be established from the trolley 7 through theline switch 9, series contactor 15 and switching device 19 to Ground, when the motors 1 and 2 are operating in series relation. The condition just mentioned also prevents a dynamicbraking circuit from being established while, the motors 1 and 2 are energized and are operating in parallel relation.

' From the above description, it is apparent that I have provided a switching device which may be operated manually, although preferably being foot-operated, to effect (1 namic braking. Dynamic braking can e effected only when the 'motors 1 and 2 are disconnected from the source of electrical energy. By making t necessary for the motorman to dlsmount' from the car or to go to some remote or inconvenient spot to acment of circuits and in theapparatus employed, without departing from the vspirit of my invention. Idesire, therefore, to he claims. I

Iclaim as my invention: 7

1. In a control system, the combination with a motor, of a controller for governing said motor, means comprising a device for efi'ecting electrical braking of said motor, means for preventing the operation of said motor after electrical braking, and means inaccessible from said controller for rendering said preventing means inoperative.

2. In a control system, the combination with a motor, of a controller for governing said motor, means comprising a pedal device for effecting dynamic braking of said motor, means for preventing the operation of said motor after dynamic braking, and means inaccessible from said controller for rendering said preventing means inoperative.

3. In a control system, the combination with a plurality of motors, of a controller for governing said motor, means comprising a device for effecting dynamic braking of said motors, means for preventing the operation of said motors upon the occurrence of dynamic braking, and means inaccessible from said controller for renderlimited only-by the scope of the appended ing said preventing means inoperative.

4. In a control system, the'combination with a motor, of a controller having an off position and an operating position for governing said motor, and means comprising a switch for effecting electrical braking of said motor, said means being operative only upon said controller occupying its off position. I

5. In a control system, the combination with a motor, of a line switch for energizing said motor, means comprising a pedal device for effecting dynamic braking of said motor and means for preventing the operation of said pedal device upon said line switch occupying its closed position.

6. In a control system, the combination with a motor, of a line switch for energizing said motor, means comprising a switching device for eflecting dynamic braking of said motor, means for preventing the operation of said device upon said line switch occupying its closed position, and means for preventing the closure of said line switch upon said device occupying its dynamic-braking position.

7. The combination with a vehicle and a motor mounted upon said vehicle, of means for effecting electrical braking of said mo tor, means for preventing the energization of said motor after said braking, and means mounted upon a relatively inaccessible portion of said vehicle for rendering said preventing means inoperative 8. The combination with a vehicle and a plurality of motors mounted upon said vehicle, of a line switch for energizing said motors, a master controller having an ofl" position and a plurality of operating positions for governing said switch, means comprising a pedal device for elfecting dynamic braking of said motors, means for preventing said device from operating prior to said master controller being returned to its off position, means for preventing the closure of said switch when said device occupies its dynamic-braking position, and a latching device for maintaining said pedal device in its dvnamic-braking position.

In testimony whereof. I have hereunto subscribed my name this 6th day of July, 1921.

HARRY R. MEYER. 

